1. Field of the Invention
The present invention relates to display devices in which pixel defects can be restored, and is suitably applicable to liquid crystal display devices, in particular.
2. Description of the Related Art
An active-matrix-driving liquid crystal display device is configured in such a way that switching devices such as TFTs (Thin Film Transistor) are connected to pixel electrodes arranged in a matrix on one of a pair of insulating substrates to be bonded with each other, and selection or non-selection of each pixel electrode is implemented through switching operation by the switching device, thereby carrying out display operation. In general, a TFT has a multi-layer structure in which a semiconductor layer, an insulating layer, and various kinds of electrodes for driving a liquid crystal are stacked up; therefore, in order to produce a TFT, deposition of each layer on an insulating substrate and patterning is repeatedly carried out. As a result, in the case where a switching device is produced, a defect may occur in which normal switching operation is not implemented due to breaking of wires or short-circuiting. In this case, a pixel consisting of a pixel electrode connected to a defective switching device becomes a defective pixel to which no voltage is applied. There has been a problem in that, especially in a liquid crystal display device in a normally-white-mode in which, when the power supply is OFF, a display screen is set to be white, the defective pixel makes a luminescent-point defect through which light is always transmitted.
In this regard, in order to make luminescent-point defects in a liquid crystal display device inconspicuous, a method has been disclosed (e.g., refer to Japanese Laid-Open Patent Publication No. 1997-179143) in which, by irradiating a laser beam onto a portion, corresponding to a pixel having a luminescent-point defect, where the drain electrode and the gate wiring overlap each other and creating a short-circuit between the drain electrode and the gate wiring that have been separated by an insulating film, and by making the voltage supplied to the gate wiring always be supplied to the drain electrode and making the pixel be always in a power-on state, the luminescent-point defect is turned to a dark-point defect, thereby being made inconspicuous.